Film winding apparatus



Aug. 12, 1969 T. D. STIEGLER ET AL 3,460,776

FILM WINDING APPARATUS Filed Dec. 7, 1967 [OHM-TENSION FIG.!

2 Sheets-Sheet l INVENTORS THEODORE DONALD STIE'GLER JAMES PHILLIP JAIGSIK EDWARD BRANTLEY BURNS ROLL DIAMETER- ATTORNEY Aug. 12, 1969 T. D. STIEGLER ET AL 3,460,776

FILM WINDING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 7,- 1967 FIG.4

ROLL DIAIIEIER INVENTORS THEODORE DONALD STIEGLER JAMES PHILLIP JANOSIK EDWARD BRANTLEY BURNS ATTORNEY United States Patent 3,460,776 FILM WlNDlNG APPARATUS Theodore Donald Stiegler, James Phillip Janosik, and Edward Brantley Burns, Richmond, Va., assignors to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Dec. 7, 1967, Ser. No. 688,758 Int. Cl. B6511 77/00 US. Cl. 242-4553 6 Claims ABSTRACT OF THE DISCLOSURE An apparatus for winding film material into roll from upon a mandrel driven by a pneumatically operated drive system in which the winding torque delivered by the drive system is controlled by a variable pressure signal which is a function of the diameter of the winding roll as determined by an associated diameter sensing assembly.

The present invention relates to winding apparatus and, more particularly, is directed to improvements in and relating to film winding apparatus having an adjustable speed drive utilizing a pneumatic control assembly and a method for winding films associated therewith.

Film winding operations are employed in many manufacturing processes such as in the manufacture of selfsupporting cellophane and thermoplastic film structures, coating regenerated cellulose films, and slitting of all types of packaging and industrial films. Variation in film tension within a roll causes many difficulties and should be avoided. For example, a uniform or constant tension on the film throughout the winding operation generally results in telescoping of the wound rolls if the tension level is too low and damaging of film layers adjacent to the roll core if the tension level is too high. Also, a constant torque windup is totally inadequate when the diametral change exceeds a ratio of approximately three-to-one during the roll forming operation. In such cases, the outer layers of film on the roll are too loose and the entire roll formation is in jeopardy of being lost. Thus, it is desirable when winding a film material into roll form to avoid variations in tension on the film during the winding operation in order to obtain a roll wherein the wound material is preferably characterized by a tapered tension that is either linear or non-linear between the core of the roll and the outer peripheral edge thereof.

The specific tension pattern imposed on a film being wound is usually selected after consideration of the type and guage of film being processed and upon the size of wound rolls desired. A tapered tension pattern is commonly employed with the degree of taper and average tension level selected in consideration of the aforementioned critical variables. Attempts have been made to provide winding apparatus having electrically operated winding tension control mechanisms, e.g., US. Patent 2,990,484, but although such apparatus perhaps effects some improvement over apparatus without any tension control device, these are largely inadequate and fail to provide a satisfactory solution to the web winding problem associated with winding operations that are conducted in hazardous environments such as the solvent coating area of a regenerated cellulose film manufacturing operation wherein the atmosphere in such an area contains lacquer solvent vapors which precludes the use of electrical spark producing equipment.

According to the present invention there is provided a film winding apparatus utilizing a pneumatically operated drive system and a film winder, including means for effecting a controlled film tension pattern from start-up to completion of a wound roll of film.

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The nature and advantages of the invention will be more clearly understood by the following description, the appended claims, and the several views illustrated in the accompanying drawings wherein like reference characters refer to the same parts throughout the several views and in which:

FIGURE 1 is a schematic representation in perspective of the functioning parts of the salient portions of the winding apparatus together with the pneumatically operated control system;

FIGURE 2 is a perspective view similar to FIGURE 1 of another embodiment of the apparatus of the present invention;

FIGURE 3 shows a torque and tension pattern for winding film material on a large core; and.

FIGURE 4 shows a typical curve of the variation in pressure of compressed air supplied to an air motor during a winding operation.

The apparatus herein disclosed in illustration of the invention includes a mandrel 10 suitably rotatably mounted in support members 11 and 12. Mandrel 10 is axially driven by suitable means 13 such as, for example, a combination belt 14 and pulley 15 assembly operatively connected thereto. Mandrel 10 is adapted to support a winding core 16 which may be removably secured thereto by conventional chuck means (not shown) adapted to receive a moving film material 17 which when wound on core 16 provides roll 18. As shown, drive means 13 is mechanically connected to power output shaft 19 and pulley 20 of pneumatic motor 21. The energy source for motor 21 is preferably compressed air which is admitted thereinto by means of conduit 22. Part of the potential and kinetic energy of the compressed air admitted into motor 21 is converted to power by the motor and transmitted to the windup mandrel 10 via power output shaft 19 and drive means 13. There are no clutches or variable speed transmission drives employed, or even required, in the power train above described. In operation, moving film material 17 is advanced at a controlled speed either directly from a manufacturing operation of from a conventional film advancing roller set (not shown) which advances the film at a controlled speed for winding on core 16.

When any windup apparatus such as shown in FIG- URE 1 is used to wind film material into roll form at a constant rate of speed, the rpm. of the roll and the di ametral change of the roll vary inversely with each other. Thus, when the film is directly adjacent core 16 during the initial phase of the winding operation the required r.p.m. of the roll is at a maximum. However, if the torque output of motor 21 is initially programmed as that necessary to provide satisfactory film tension on core 16 at the conclusion of the winding operation and is thereafter maintained at this level, then the torque output during most of the winding operation will be too great which can cause crushing of core 16 and severe damage to the wound film material.

The present invention provides a source of compressed air at controlled pressure to be admitted into pneumatic motor 21 during the roll forming operation. The pressure control is achieved by using the sum of two basic pneumatic signals. The first pneumatic signal is of constant magnitude sufficient to operate motor 21 to provide an adequate tension level in the film material being wound at the beginning of the film winding operation. The second pneumatic signal is a function of the diameter of the winding roll and effects either an increase or a decrease in the torque output of pneumatic motor 21 for driving mandrel 10 as thed iameter of the forming roll 18 constantly increases during the winding operation.

Referring again to FIGURE 1, the pneumatic signal of constant magnitude is provided by a dead-end type pressure regulator 23 having manual pressure control means 24 and supplied with constant pressure compressed air from a suitable source thereof (not shown) by means of conduit 25. The compressed air in conduit 25 reaches pressure regulator 23 by means of conduits 26 and 27. The constant pressure pneumatic signal generated by the pressure regulator 23 is transmitted by means of conduit 28 to a penumatic summation relay 29 which will be described in detail herebelow. The pressure regulator 23 is a conventional unit and any as are well known in the trade may be employed such as, for example, pressure regulator Model No. FH-6OXT-K1 having a 0-125 p.s.i.g. operating range available from the Conoflow Corporation.

The second pneumatic signal above mentioned is provided by a cooperative association of means comprising rotatable means 30, lever 31 and pneumatic transmitter 32. The rotatable means 30 preferably consists of a wheel or hearing rotatably secured to the end of lever 31 and adapted to contact the surface of roll 18 whereby to continually follow the diametral change thereof during the winding operation. The lever 31 is pivotally connected at 33 to fixed rod or bar 34 that is secured at its ends to extension arms 35 and 36 of support members 11 and 12. Lever 31 is provided with a cam surface 37 on its other end. As can be seen from FIGURE 1, lever arm 31 is adapted to pivot at 33 as the diameter of roll 18 increases. A pneumatic position transmitter 32 having position sensing means such as outwardly extending shaft 38 is mounted in cooperative association with lever 31 so that the end of the position sensing shaft 38 abuts and follows the cam surface 37 of lever 31. The pneumatic position transmitter 32; is operatively connected to a source of constant pressure compressed air (not shown) by means of conduits 25 and 26 and is adapted to generate an output pneumatic signal, herein denominated the variable pressure signal, that is proportional to the displacement of position sensing shaft 38 which is in turn responsive to movement of lever 31 during the roll winding operation. The variable pressure signal is transmitted to pneumatic summation relay by means of conduit 39. Pneumatic position transmitter 32 is a conventional unit and any as are well known in the trade may be employed such as, for example, position indicator valve Model No. 104NF3119 available from the Taylor Instrument Co.

The constant pressure signal and the variable pressure signal above described are monitored by the pneumatic summation relay 29 which is operatively connected to a source of constant pressure compressed air (not shown) by means of conduit 25. Pneumatic summation relay 29 sums the signals to provide a combined signal used to generate in turn a pneumatic output signal that is pr0- portional thereto. The pneumatic signal generated by pneumatic summation relay 2? is transmitted by means of conduit 4%) to pilot operated valve 41 which is supplied with a source of constant pressure compressed air (not shown) by means of conduit 42. Pilot operated reducing valve 41 reduces the pressure of the compressed air entering thereinto via 4-2 in a constantly changing manner so that the pressure of the compressed air admitted into conduit 22 incrementally decreases and/or increases as the diameter of the winding roll 18 increases. The pneumatic summation relay-29 and the pilot operated reducing valve 41 may be combined into a single unit having a single outlet connected directly to conduit 22 and air motor 21.

In another embodiment of the apparatus of the present invention, the summation relay 29 has only a single pneumatic signal source as from pneumatic position transmitter 32 and means incorporated thereinto for setting the equivalent of the constant pressure signal; such means may comprise an adjustable spring operatively connected to the actuating signal producing means of the relay valve 29. Thus, the pneumatic signal produced by relay valve 29 is proportional to the sum of the force produced by the adjustable spring and the force produced by the bellows receiving the pneumatic signal from the pneumatic position transmitter 32. As can be seen from FIGURE 2, this embodiment of the invention eliminates the need for the pressure regulator 24 and permits comparable control with fewer operating components.

FIGURE 3 shows the preferred torque/tension vs. roll diameter curves for winding film materials when the diametral change in the wound roll due to winding approaches or exceeds a 3 to 1 ratio. The curves, as shOWn, are typical for an 8.5" to 24" diametral change in the wound roll. The preferred torque relationship shown varies as an approximate straight line relationship with the diameter of the winding roll. Since torque equals the tension times the wound roll radius, it is seen that the tension in this preferred winding pattern varies as the sum of the slope of the torque curve and an inverse function of the first power of the diameter. This is in direct contrast to the tension pattern normally attained by use of an air motor whereby the tension in the web material varies as the sum of an inverse function of the second power of the roll diameter. The preferred tension pattern shown in FIGURE 3 can be achieved in a centerwinding operation by constantly varying the pressure of the compressed air admitted to the air motor as the winding roll diameter constantly increases. FIGURE 4 shows this air pressure viriation for a typical 8.5 to 24" roll diameter buildup. The ordinate scale is discontinuous in order to emphasize the constantly changing characteristics of the curve. The actual magnitude of change in the air pressure to the air motor is approximately an initial cumulative reduction of 10% followed by a cumulative pressure increase of about 60% of the initial reduction.

The tensile loading on the web when the air motor is actuated by varying pressure compressed air as shown in FIGURE 4 constantly decreases but not as drastically as it would under the constant torque operation. The configuration of the operating torque curve and correspondingly the operating tension curve can be varied to meet the requirements of film type, film width, and film speed by varying the level of the compressed air source to conduit 19 and by changing the geometry of the cam surface 37 shown in FIGURE 1 relative to its peripheral relationship with fulcrum point 33. Windup curves of constant torque, constant tension, decreasing tension, etc., thus can be designed into the apparatus and can be achieved by all pneumatic means. Additionally, torque/ r.p..m. relationships may be conveniently changed at the windup mandrel 10 shown in FIGURE 1 by changing the speed reduction ratio of the drive means 13. Windup film tension patterns can be maintained in this manner when changing the desired diametral proportions of the winding roll.

What is claimed is:

1. A method for winding a film of material into roll form on a mandrel operatively connected to pneumatic drive means which comprises: supplying a compressible fluid at an initial pressure level to said drive means whereby to provide the desired level of film tension at the be ginning of the roll formation, and thereafter varying the initial pressure level of said compressible fluid in increments as a function of the change in the diameter of said roll for effecting a controlled film tension pattern of said roll.

2. A method for winding a film of material into roll form utilizing a pneumatically operated drive system which comprises generating a first pneumatic signal of preselected pressure, generating a second pneumatic signal of variable pressure as a function of the diameter of said roll, combining said first and second pneumatic signals and generating a third pneumatic signal for varying the pressure of a fixed source of compressible fluid in incremental steps as a function of the change in magnitude of said third pneumatic signal for operating said pneumatic drive system with said compressible fluid for efiecting a controlled film tension pattern of said roll.

3. Winding apparatus comprising a rotatable member adapted to be rotatably driven to wind film material into roll form thereon, drive means operatively connected between said rotatable member and pneumatic means adapted to transmit motive power to said drive means responsive to a control signal from a tension control means adapted to generate a control signal responsive to the diameter of said roll for effecting a controlled film tension pattern of said roll.

4. A winding apparatus comprising a mandrel supported for rotational movement and adapted to support a core for winding film material thereon, means operatively connected to said mandrel for driving said mandrel including an air motor having an air inlet port, means for generating a first pneumatic signal of preselected pressure, means for generating a second pneumatic signal as a function of the diameter of said roll, and means for combining said pneumatic signals and generating a control pneumatic signal for operating pressure regulator means of the pilot operated type operatively connected thereto, said pressure regulator means having a source of compressed air and being operatively connected to said air motor for regulating the supply of compressed air to said air motor responsive to said control pneumatic signal.

5. A Winding apparatus comprising a mandrel supported for rotational movement and adapted to support a core for winding film material thereon, means for driving said mandrel operatively connected thereto including an air motor having a compressed air inlet port, means contacting the surface of said film on said core secured to one end of lever means pivotally supported intermediate its ends and having a cam surface at its other end, a pneumatic position indicator having position indicating means contacting said cam surface and operatively connected to a source of compressed air for generating a pneumatic signal in direct response movement of said lever means, and means for generating a preselected pneumatic signal, a pneumatic summation relay for combining said pneumatic signals and generating a control pneumatic signal responsive thereto, and a pressure regulator of the pilot operated type operatively connected to said pneumatic summation relay and a source of compressed air and being operatively connected to said air motor for regulating the supply of compressed air to said air motor responsive to said control pneumatic signal.

6. An apparatus for winding a continuous length of film material onto a core in roll form comprising in combination: a frame having spaced support members secured thereto; a mandrel rotatably supported between said support members adapted to support a core for Winding film material thereon; an air motor mounted on said frame having a compressed air inlet and a power output shaft; a driving means operatively connected between the output shaft of the air motor and said mandrel; follower means positioned to follow the surface of said roll as its diameter increases, said follower means connected to one end of lever means having a cam surface at its other end and pivotally supported intermediate its ends for pivotal movement responsive to the diametral change in said roll; a pneumatic position indicator having means contacting said cam surface and connected to a source of compressed air for generating a pneumatic signal as a function of the diametral change in said roll; a pressure regulator operatively connected to a source of compressed air for generating a preselected pneumatic signal; a pneunatic summation relay for combining said pneumatic signals and generating a control pneumatic signal which is the sum of the first and second pneumatic input signals; and a second pressure regulator of the pilot operated type operatively connected to said pneumati summation relay and a source of compressed air and being operatively connected to said air motor for regulating the supply of compressed air to said air motor responsive to said control pneumatic signal.

References Cited UNITED STATES PATENTS 2,984,431 5/1961 North 242--75.53 3,053,468 9/1962 Zernov et al. 242-75.53 3,112,086 11/1963 Garten 242--6-7.5

LEONARD D. CHRISTIAN, Primary Examiner US. Cl. X.R. 242-67 

